Flexible bone plates and methods for dynamic spinal stabilization

ABSTRACT

A plating system and method include a bone plate with at least a first vertebral engaging portion and a second vertebral engaging portion connected by flexible intermediate portions to permit translation of the vertebrae to which the bone plate is attached. The bone plate may further include a guide assembly extending between the vertebral engaging portions that permits at least uni-directional translation while enhancing resistance of the bone plate to bending forces.

BACKGROUND

Bone plates can be engaged to adjacent bony portions of a bone or of abony segment to stabilize the bony portions. Anchors or fasteners, suchas bone screws, can be used to engage bone plates to the bony portions.In spinal surgical procedures, it can be desirable to provide stress onan interbody implant positioned between vertebrae to promote bone growthand fusion of adjacent vertebrae. Plates that rigidly maintain theseparation distance between vertebrae can shield bone graft from stressand can result in less than optimal bone growth and fusion of thevertebrae.

There remains a need for devices and methods that can be employedefficiently and effectively for stabilizing one or more levels of aspinal column while preventing stress shielding of bone graft positionedto fuse the one or more levels.

SUMMARY

There is provided a spinal plating system with a plate body that canflex or deform in response to compression loading of the spinal columnto maintain loading on bone graft in a disc space between vertebrae towhich the plate is engaged. The plate can include a guide assembly thathas a guide member movably received in a receptacle at least in responseto compression loading. The guide assembly can provide resistance tobending forces exerted on the plate as a result of extension and flexionof the spinal column.

According to another aspect, a spinal plating system includes a platebody extending along a longitudinal axis between a first end and anopposite second end. The plate body has a length along the longitudinalaxis sized to extend between at least a first vertebra and a secondvertebra of the spinal column. The plate body includes first and secondvertebral engaging portions each with at least one hole extendingbetween an upper surface and a lower surface of the plate body toreceive an anchor to secure the vertebral engaging portions torespective ones of the first and second vertebrae. The plate body alsoincludes first and second intermediate portions extending between thefirst and second vertebral engaging portions along opposite sides of theplate body. The first and second intermediate portions and the first andsecond vertebral engaging portions define a window therebetween. Thefirst and second intermediate portions are structured to flex and permitthe first and second vertebral engaging portions to move toward oneanother along the longitudinal axis in response to compression loadingalong the longitudinal axis. The plating system also includes a guideassembly in the window along the longitudinal axis extending between andengaged to the first and second vertebral engaging portions. The guideassembly includes a guide member movably received in a receptacle as thefirst and second vertebral engaging portions move toward one another.

According to another aspect, a spinal plating system includes a platebody extending along a longitudinal axis between a first end and anopposite second end. The plate body has a length along the longitudinalaxis sized to extend between at least first and second vertebrae of thespinal column. The plate body includes first and second vertebralengaging portions each with at least one hole extending between an uppersurface and a lower surface of the plate body to receive an anchor tosecure the first and second vertebral engaging portions to respectiveones of first and second vertebrae. The plating system also includes aretaining element adjacent the upper surface associated with at leastone of the plate holes. The retaining element includes a number ofresilient fingers circumferentially positioned about the at least onehole. The fingers are separated from one another by a groove and eachfinger includes a first leg extending proximally from the plate body anda second leg at an end of the first leg extends radially inwardly towardthe other fingers.

According to another aspect, a spinal plating system includes a platebody extending along a longitudinal axis between a first end and anopposite second end. The plate body has a length along the longitudinalaxis sized to extend between at least a first vertebra and a secondvertebra of the spinal column. The plate body includes first and secondvertebral engaging portions each with at least one hole extendingbetween an upper surface and a lower surface of the plate body. The atleast one holes each receive an anchor to secure the respective firstand second vertebral engaging portions to respective ones of the firstand second vertebrae. The plating system also includes at least oneintermediate portion extending between the first and second vertebralengaging portions having opposite ends integrally fixed with respectiveones of the first and second vertebral engaging portions to form aunitary structure. The at least one intermediate portion is structuredto deform and permit the first and second vertebral engaging portions tomove toward one another along the longitudinal axis in response tocompression loading along the longitudinal axis. The plating system alsoincludes a guide assembly extending between and engaged to the first andsecond vertebral engaging portions. The guide assembly includes a guidemember movably received in a receptacle as the first and secondvertebral engaging portions move toward one another.

In yet another aspect, a method for stabilizing at least one level of aspinal column comprises: engaging a first vertebral engaging portion ofa spinal plate to a first vertebra with at least one anchor extendingthrough the first vertebral engaging portion; engaging a secondvertebral engaging portion of the spinal plate to a second vertebra withat least one anchor extending through the second vertebral engagingportion, wherein the spinal plate includes a longitudinal axis extendingalong the first and second vertebrae when engaged to the first andsecond vertebrae; and compressing the first and second vertebrae to flexat least one intermediate portion extending between the first and secondvertebral engaging portions, the intermediate portion lying in a planein which the first and second vertebral engaging portions lie and beingstructured to flex in the plane transversely to the longitudinal axis topermit movement of the first and second vertebrae toward one another.

These and other aspects are discussed further below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a top plan view of one embodiment spinal plate.

FIG. 2 is a top plan view of another embodiment spinal plate.

FIG. 3 is a top plan view of a guide member comprising a portion of thespinal plate of FIG. 2.

FIG. 4 is an elevational view of the guide member of FIG. 3.

FIG. 5 is a top plan view of a receptacle of the spinal plate of FIG. 2.

FIG. 6 is an end elevational view of the receptacle of FIG. 5.

FIG. 7 is a top plan view of another embodiment spinal plate.

FIG. 8 is a top plan view of another embodiment spinal plate.

FIG. 9 is a section view along line 9-9 of FIG. 8.

FIG. 10 is a top plan view of a plate body of the spinal plate of FIG.8.

FIG. 11 is a section view along line 11-11 of FIG. 10.

FIG. 12 is a plan view of a guide member employed with the spinal plateof FIG. 8.

FIG. 13 is an elevational view of the retaining arm of FIG. 12.

FIG. 14 is a top plan view of another embodiment spinal plate.

FIG. 15 is a section view along line 15-15 of FIG. 14.

FIG. 16 is a section view along line 16-16 of FIG. 14.

FIG. 17 is a top plan view of another embodiment spinal plate with boneanchors.

FIG. 18 is an elevational view of the spinal plate and bone anchors ofFIG. 17.

FIG. 19 is an elevational view of one of the bone anchors of FIG. 17.

FIG. 20 is a top plan view of the spinal plate of FIG. 17.

FIG. 21 is a section view along line 21-21 of FIG. 20.

FIG. 22 is an enlarged, detailed view of the region 22 indicated in FIG.21.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is hereby intended, such alterations and further modificationsin the illustrated devices, and such further applications of theprinciples of the invention as illustrated herein being contemplated aswould normally occur to one skilled in the art to which the inventionrelates.

Bone plates are engageable along two or more vertebrae of a spinalcolumn to stabilize one or more levels of the spinal column. Suchstabilization can be employed, for example, to maintain or control adesired relative positioning between the vertebrae during fusion. Thebone plates can be engaged to the vertebrae with bone anchors, and mayinclude one or more retaining elements associated with one or more ofthe fasteners to prevent the fasteners from backing out relative to theplate. The bone plates include at least one intermediate portionextending between first and second vertebral engaging portions. The atleast one intermediate portion can bend and flex in response to loadingapplied to the plate to allow movement of the vertebral engagingportion, and thus the vertebrae engaged thereto, toward and away fromone another. The bone plates can also include a guide assembly extendingbetween the vertebral engaging portions to provide strength to the boneplate to resist bending forces applied to the bone plate resulting fromflexion and extension of the vertebral levels while allowing movement ofthe vertebral engaging portions relative to one another as result of atleast compression forces.

Referring now to FIG. 1 there is shown a spinal plate 30 having aplate-like body 32 extending along a longitudinal axis 31 between afirst end 34 and an opposite second end 36 with a length sized to extendbetween vertebrae of at least one vertebral level. Plate 32 includes anupper or proximal surface 32 a and an opposite distal lower surface thatis positionable along the vertebrae. The lower surface can be curvedabout and/or along longitudinal axis 31 to conform to the profile of theadjacent vertebrae. Sidewalls 38, 40 extend along opposite sides of body32 between first and second ends 34, 36.

Body 32 includes a first vertebral engaging portion 46 adjacent firstend 34 and a second vertebral engaging portion 48 adjacent second end36. Body 32 also includes a pair of holes 42 a, 42 b adjacent first end34 in first vertebral engaging portion 46, and a second pair of holes 44a, 44 b adjacent second end 36 in second vertebral engaging portion 48.Holes 42 a, 42 b and holes 44 a, 44 b are located on opposite sides oflongitudinal axis 31, and are configured to receive a bone anchor, suchas a bone screw, to secure plate 30 to a vertebral body underlying plate30 at the respective vertebral engaging portions 46, 48. Otherembodiments contemplate that plate 30 can be provided with a single holein one or both of the vertebral engaging portions 46, 48, or with morethan two holes in one or both of the vertebral engaging portions 46, 48.Holes 42 a, 42 b, 44 a, 44 b can include spherically-shaped recessedportions 43 a, 43 b, 45 a, 45 b, respectively, adjacent upper surface 32a to allow the bone anchors to recess into plate 30 and reduce theprofile of the assembly when attached along the spinal column.

First vertebral engaging portion 46 and second vertebral engagingportion 48 can be connected with one another via flexible or deformableintermediate portions 50 a, 50 b extending therebetween. Intermediateportions 50 a, 50 b each have a width 52 transverse to longitudinal axis31 that is substantially smaller than a width of window 54 betweenintermediate portions 50 a, 50 b. The ends of intermediate portions 50a, 50 b can be integrally formed with and immovably fixed to therespective adjacent vertebral engaging portion 46, 48 to form a unitarystructure. Intermediate portions 50 a, 50 b are located along respectiveones of the sidewalls 38, 40 of plate body 32. A window 54 extendsthrough body 32 between intermediate portions 50 a, 50 b and betweenvertebral engaging portions 46, 48. Intermediate portions 50 a, 50 b canbe convexly curved away from longitudinal axis 31 to form a bowed orarcuate shape. When plate 30 is positioned anteriorly along vertebrae,intermediate portions 52 a, 52 b are bowed laterally outwardly.

The ends of intermediate portions 50 a, 50 b can be immovably fixed tovertebral engaging portions 46, 48. Intermediate portions 50 a, 50 b canbe integrally and unitarily formed with vertebral engaging portions 46,48 to provide a one-piece plate body 32 that can flex or deform inresponse to compressive loads 66. In particular, the bowed or arcuateshape and relatively small width of intermediate portions 50 a, 50 ballow flexing or deforming of intermediate portions 50 a, 50 b laterallyoutwardly away from longitudinal axis 31, as indicated by arrows 68. Thedeformation or bowing of intermediate portions 50 a, 50 b occurs in thesame plane in which vertebral engaging portions 46, 48 lie, andtherefore intermediate portion 50 a, 50 b do not impinge on the discspace or the tissue along upper surface 32 a of plate 30 when it isengaged to the spinal column. In addition, first and second vertebralengaging portions 46, 48 can move toward and away from one anotherwithout sliding movement of two or more portions of the plate bodyrelative to one another.

First vertebral engaging portion 46 includes a first transverse wall 60extending along one side of window 54 and second vertebral engagingportion 48 includes a second transverse wall 62 extending along theother side of window 54. As body 32 of plate 30 is axially compressedalong longitudinal axis 31, transverse walls 60, 62 move toward oneanother reducing the height of window 54. In addition, as body 32 ofplate 30 is axially tensioned, transverse walls 60, 62 move away fromone another thereby enlarging window 54.

Body 32 can be subject to bending moments as the vertebrae to whichplate 30 is attached move toward and away from one another during spinalextension and flexion. Spinal plate 30 can include a guide assembly 70between vertebral engaging portions 46, 48 that guide movement ofvertebral engaging portion portions 46, 48 relative to one another asplate 30 flexes and also to provide cross-sectional area to resistbending forces created by spinal extension and flexion motion.

Guide assembly 70 can include a guide member 58 that is axially receivedin and movable relative to a guide receptacle 56. In the illustratedembodiment, guide member 58 extends axially along axis 31 from secondtransverse wall 62 toward first vertebral engaging portion 46, andreceptacle 56 extends along axis 31 from first transverse wall 60 towardsecond vertebral engaging portion 48. Guide member 58 is axiallyreceived in an opening into receptacle 56 and guided in receptacle 56 asfirst and second vertebral engaging portions 46, 48 move toward and awayfrom one another. Guide member 58 can include a rectangular shape thatis received through a complementary-shaped opening of receptacle 56 intoa similarly shaped cavity defined by receptacle 56 to limit rotationalor twisting movement between vertebral engaging portions 46, 48.

Other embodiments contemplate that guide member 58 can extend from firstvertebral engaging portion 46, and receptacle 56 can extend from secondvertebral engaging portion 48. Guide member 58 and receptacle 56 can beseparate components, and body 32 of plate 30 can be molded around guidemember 58 and receptacle 56. In another embodiment, guide member 58 andreceptacle 56 are attached with body 32 after formation of body 32.

In FIG. 2 there is shown another embodiment plate 130 that issubstantially like plate 30 discussed above, and like elements aredesignated with the same reference numerals. Spinal plate 130 includesanother embodiment guide assembly 170. Guide assembly 170 includes aguide member 158 and a receptacle 156 for receiving guide member 158.Guide assembly 170 differs from guide assembly 70 in that receptacle 156and guide member 158 have a ratcheting configuration that permitsunidirectional translation while resisting translation in the oppositedirection.

FIGS. 3-4 show guide member 158 in isolation and FIGS. 5-6 showreceptacle 156 in isolation. Guide member 158 includes a body portion140 having a retaining arm 142 at one end thereof. Retaining arm 142 canfacilitate molding or attachment of plate body 32 around or to guidemember 158. Body portion 140 also includes a toothed surface portion 144along a surface thereof. Toothed surface portion 144 includes a numberteeth 146 projecting therefrom. Teeth 146 each include a verticallyoriented wall portion 148 and a sloped wall portion 150. As shown inFIG. 2, guide member 158 can be engaged with one of the vertebralengaging portions 46, 48 and extend axially therefrom toward the othervertebral engaging portion 46, 48.

Receptacle 156 includes a body 160 that defines a cavity 162 sized andshaped to receive body portion 140 of guide member 156 as shown in FIG.2. An end of body 160 opposite the opening of cavity 162 includes aretaining arm 166 that facilitates molding or attachment of receptacle156 to plate body 32. Body 160 also includes a retaining lip 164extending into cavity 162.

When guide member 158 and receptacle 156 are assembled with body 32 ofplate 130, retaining lip 164 is positionable in contact with toothedsurface portion 144 and engageable with an aligned one of the teeth 146of toothed surface portion 144. Retaining lip 164 can include avertically oriented wall portion 168 that abutting engages verticallyoriented wall portion 148 of the engaged tooth 146 to prevent vertebralengaging portions 46, 48 from moving away from one another. Ascompression loads are applied to vertebral engaging portions 46, 48,retaining lip 164 can slide along sloped surface 150 of the nextadjacent tooth 146 until wall portion 168 is aligned with the verticallyoriented wall portion 148 of the next adjacent tooth 146.

Referring now to FIG. 7, there is shown another embodiment plate 230that can be substantially identical to plate 30 discussed above, andlike elements are designated with like reference numerals. However,plate 230 includes another embodiment guide assembly 270 that has aguide member 258 extending axially from one of the vertebral engagingportions 46, 48 and a receptacle 256 extending axially from the other ofthe vertebral engaging portions 46, 48 and positioned to receive guidemember 258. Unlike guide assembly 170 discussed above, guide member 258is sized relative to window 54 and receptacle 256 so that when plate 230is in its normal, uncompressed state, guide member 258 is not receivedin receptacle 256. Accordingly, guide member 258 and/or receptacle 256can be formed integrally with body 32 to provide a spinal plate 230having a unitary, one-piece construction of guide assembly 270 and platebody 32.

Guide member 258 can include a toothed surface 244 like guide member 158discussed above, and receptacle 256 can including a retaining lip 264oriented toward the toothed surface 244. When plate 230 is attached tothe spinal column, it can flex in response to compression and tensionloads with resistance provided by plate body 32 but not guide assembly270. When the compression forces are great enough, body 32 can flexsufficiently to position guide member 258 in receptacle 256 with theretaining lip 264 engaged to the toothed surface 244. In thisconfiguration, translation is uni-directionally controlled and movementof the vertebrae away from one another is limited by guide assembly 270in addition to body 32.

Referring now to FIGS. 8-9, there is shown a spinal plate 330 thatincludes a plate body 332 that is similar to plate body 32 discussedabove and like elements are designated with like reference numerals.Body 332 differs from body 32 in that it includes a vertebral engagingportion 348 defining an internal and axially extending guide memberretaining passage 350. Spinal plate 330 also includes another embodimentguide assembly 370 with a guide member 358 removably engageable inretaining passage 350, and vertebral engaging portion 48 includes areceptacle 356 for receiving guide member 358.

Guide member retaining passage 350 is shown with the depiction of platebody 332 in FIGS. 10-11 with guide member 358 removed. Retaining passage350 includes a first enlarged end portion 352 adjacent one end of platebody 332 and an opposite enlarged second end portion 353 adjacent towindow 54. Guide member 358, shown in isolation in FIGS. 12-13, includesa body portion 340 having a toothed surface with teeth 346 extendingthereacross. Guide member 358 further includes a mounting portion 341with first and second legs 342 a, 342 b extending from body portion 340that are separated by a slot 345. The ends of legs 342 a, 342 b remotefrom body portion 340 include a respective one of the retaining flanges344 a, 344 b projecting outwardly therefrom. Sloped wall surfaces 343 a,343 b extend along the opposite sides of flanges 344 a, 344 b and tapertoward one another in the direction extending away from body portion340.

Guide member 358 can be inserted into retaining passage 350 with slopedsurfaces 343 a, 343 b contacting the inner sides of retaining passage350 to compress legs 342 a, 342 b toward one another along slot 345 toallow legs 342 a, 342 b to move along retaining passage 350. Whenflanges 344 a, 344 b are aligned with enlarged end portion 352 ofretaining passage 350, legs 342 a, 342 b can spring outwardly to engageflanges 344 a, 344 b in enlarged end portion 352. A part of body portion340 resides in enlarged end portion 353 of passage 350, securing guidemember 358 in vertebral engaging portion 348.

As shown in FIGS. 8-9, guide member 358 extends from retaining passage350 toward receptacle 356. Receptacle 356 includes a retaining lip 360engageable with an adjacent one of the teeth 346 as plate body 332 iscompressed under compression loading. Engagement of retaining lip 360with the adjacent tooth 346 limits movement of the vertebral engagingportions and thus the vertebrae away from one another while allowingunidirectional translation in compression to maintain graft loading.

FIGS. 14-16 show another embodiment spinal plate 430 having a plate body432. Body 432 is similar to body 32 discussed above, but plate 430includes another embodiment guide assembly 470 and a vertebral engagingportion 446 that is configured to interact with the same. Vertebralengaging portion 446 includes a receptacle 456 having a number ofretaining lips 460 extending thereacross. Vertebral engaging portion 446also includes a slot 462 extending therealong transversely to andinterrupting retaining lips 460 that also opens into receptacle 456.

Vertebral engaging portion 48 includes a guide member 458 extendingtoward and positionable in receptacle 456. Guide member 458 includes aspring 444 extending thereacross that is captured in a recess 446 formedbetween side rails extending along guide member 458. As shown in FIG.17, spring 444 can flex outwardly so as to normally engage an adjacentone of the retaining lips 460 as guide member 458 is advanced intoreceptacle 456 in response to axial compression of plate 430. Engagementbetween spring 444 and the adjacent retaining lip 460 maintains thecompression load on the bone graft while resisting movement of thevertebrae away from one another. If it is desired to allow vertebralengaging portions 446, 48 to move away from one another, spring 444 canbe accessed through slot 462 and compressed to disengage spring 444 fromthe adjacent lip 460, allowing movement of vertebral engaging portions446, 48 away from one another.

FIGS. 17-22 show another embodiment plate 530 that can be configuredwith a guide assembly in accordance with any of the embodimentsdiscussed herein. In the illustrated embodiment, guide assembly 170 isshown with plate body 532. Spinal plate 530 differs from the otherspinal plate embodiments in that it is shown with a retaining elementadjacent each of the plate holes. However, it should be understood thatany of the plate embodiments may incorporate the retaining element ofFIGS. 17-22 or any other suitable device for retaining, preventing orresisting anchors from backing out of the plate holes.

Plate 530 includes a plate body 532 having a first vertebral engagingportion 546 engaged to a first vertebra V1 with anchors 600, and asecond vertebral engaging portion 548 engaged to a second vertebra V2with anchors 600. One or more implants I having bone graft and/or othersuitable bone growth promoting materials can be positioned in the discspace between vertebrae V1, V2. Engaging portions 546, 548 are movabletoward and away from one another in response to axial compression andtension loading of plate 530 via flexing of intermediate portions 550 a,550 b extending therebetween as discussed above with respect to plate30. In addition, guide assembly 170 can provide additional strength inresisting bending forces created by spinal flexion and extension, andcan include a ratcheting feature to permit uni-directional translationin axial compression only.

Body 532 defines holes 542 a, 542 b in vertebral engaging portion 546and holes 544 a, 544 b in vertebral engaging portion 548. Anchors 600can be positioned in respective ones of the holes 542 a, 542 b, 544 a,544 b to engage plate 530 to the respective vertebrae V1, V2. Inaddition, plate 530 includes a retaining element 561 a, 561 b, 561 c,561 d extending about each of the respective holes 542 a, 543 b, 544 a,544 b. As shown with respect to retaining element 561 a in FIGS. 21-22,retaining element 561 a includes a number of fingers 562 spaced aboutthe perimeter of hole 542 a that are adjacent the upper or proximalsurface of plate 530. Fingers 562 are separated from one another bygroove 563 such that four fingers 562 are provided in the illustratedembodiment. Each finger 562 includes an L shape with a vertically orproximally extending leg 565 and a horizontally extending leg 566extending from the outer end of the respective leg 565 and radiallyinwardly toward hole 542 a. A circumferential groove 564 in the upperplate surface extends about each of the fingers 562 along first leg 565,facilitating fingers 562 in flexing radially outwardly to permitinsertion of the anchor therethrough into hole 542 a. Fingers 562 canresiliently return toward their pre-anchor insertion configuration toblock or prevent the anchor from backing out of plate hole 542 a.

One embodiment for anchor 600 is further shown in FIG. 19. Anchor 600includes a proximal head portion 602 having enlarged and generallyspherical shape extending about a distally extending shaft portion 604.An intermediate neck portion 606 can extend between head portion 602 andshaft portion 604. Head portion 602 can include an internal toolengaging recess 608 to receive and engage a driving tool. In addition,head portion 602 can include a proximally oriented retaining flange 612extending thereabout.

As anchor 600 is positioned through one of the plate holes 542 a, 542 b,544 a, 544 b, retaining element 561 allows passage therethrough sincefingers 562 deflect radially outwardly as head portion 602 comes intocontact therewith. Once head portion 602 is driven distally beyondfingers 562, the fingers 562 can return toward their unflexed conditionand engage head portion 602 proximally of or against retaining flange612, preventing anchor 600 from backing out proximally from the platehole. Anchor 600 provides a structure that can be positively engaged bythe retaining element 561 to provide a one step locking mechanism thatautomatically locks the anchor in the plate hole when the anchor isinserted. Retaining elements 561 can be machined into body 532 of plate530, molded with body 532 of plate 530, or be in the form of separatecomponents engaged to body 532 of plate 530.

The bone plates herein may include any suitable overall shape and formfor plates for spinal stabilization, including plates employed foranterior, antero-lateral, lateral, and posterior stabilizationprocedures. The plate holes for receiving the anchors can be generallycircular in shape; however, it should be appreciated that the holes canbe configured or shaped differently in any manner suitable for receiptof an anchor. For example, the holes or portions thereof can becylindrical, partially spherical, frusto-conical, elongated, oval,slotted, and combinations thereof. Further, it should be appreciatedthat holes can be provided through the bone plates either in isolation,in adjacent hole pairs, or three or more adjacent holes.

The plates discussed herein can be made from any one or a combination ofsuitable material or materials, including metals and metal alloys,polymers, biological materials, synthetic materials, and resorbablematerials, for example. In one embodiment, the body of the plate is madefrom a first material that facilitates the flexibility or deformabilityof the intermediate portions between the vertebral engaging portions,and the guide assembly is made from a second material so the componentsof the guide assembly are attached to or molded in the body of theplate. In one specific example, the plate body is made from PEEKmaterial and the guide assembly is made from a metal or metal alloy suchas titanium.

The anchors employed to attach the plate to the vertebrae can include aproximal head and a distal bone engaging portion. The bone engagingportion can include a thread pattern therealong to engage bony structureof the vertebral body underlying the plate hole through which the anchoris positioned. The bone engaging portion of the anchors includes anelongated shaft structure with a generally cylindrical shape, althoughother shapes are also contemplated, including circular, square,rectangular, polygonal shape, and any other suitable shape for passagethrough a plate hole and engagement with bony structure. When positionedin the plate hole, the head of the anchor can be fixed, pivotal,translatable or otherwise movable in the hole. It is contemplated thatthe head can extend at or at least slightly above the upper proximalsurface of the plate, or could be recessed distally below the uppersurface.

The use of a plating system by a surgeon may involve inserting retainingmembers adjacent one or more of the holes in the plate-after placementof one or more anchors in the holes of the plate. The retaining memberscan be separate components attached to the plate after implantation ofthe plate, or pre-attached to the plate and moveable relative to theplate to a position that prevents the anchors from backing out of theplate holes. After implantation and securement of the bone plate to thebony structure, the retaining member prevents and/or limits the backoutof one or more anchors relative to the plate. Specifically, theinterference between the retaining member and the head of the anchorblocks the anchor from backing out of the plate hole and out ofengagement with bony structure underlying the plate and into tissuesurrounding the plate.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character. For example, the spinalplates can extend along three or more vertebrae with one or moreflexible intermediate portions. The spinal plates can also include twoor more intermediate portions to provide multiple flexing regions. Themultiple flexible regions can be aligned with respective disc spacesalong a multi-level stabilization procedure. All changes andmodifications that come within the spirit of the invention are desiredto be protected.

1. A spinal plating system, comprising: a plate body extending along alongitudinal axis between a first end and an opposite second end, saidplate body having a length along said longitudinal axis sized to extendbetween at least a first vertebra and a second vertebra of the spinalcolumn, wherein said plate body includes: a first vertebral engagingportion with at least one hole extending between an upper surface and alower surface of said plate body, said at least one hole for receivingan anchor to secure said first vertebral engaging portion to the firstvertebra; a second vertebral engaging portion with at least one holeextending between said upper and lower surfaces of said plate body, saidat least one hole for receiving an anchor to secure said secondvertebral engaging portion to the second vertebra; first and secondintermediate portions extending between said first and second vertebralengaging portions along opposite sides of said plate body, said firstand second intermediate portions and said first and second vertebralengaging portions defining a window therebetween that opens at saidupper and lower surfaces of said plate body, wherein said first andsecond intermediate portions are structured to flex and permit saidfirst and second vertebral engaging portions to move toward one anotheralong said longitudinal axis in response to compression loading of saidplate body along said longitudinal axis, wherein each of said first andsecond intermediate portions is structured to deform laterally outwardlyaway from said longitudinal axis and permit said first and secondvertebral engaging portions to move toward one another along saidlongitudinal axis in response to compression loading of said late bodyalong said longitudinal axis; and a guide assembly in said window alongsaid longitudinal axis extending between and engaged to said first andsecond vertebral engaging portions, said guide assembly including aguide member movably received in a receptacle as said first and secondvertebral engaging portions move toward one another.
 2. The system ofclaim 1, wherein said first and second intermediate portions areintegral with said first and second vertebral engaging portions to forma one-piece unitary structure for said plate body.
 3. The system ofclaim 1, wherein said first and second intermediate portions eachinclude a first end immovably fixed with said first vertebral engagingportion and an opposite second end immovably fixed with said secondvertebral engaging portion.
 4. The system of claim 1, wherein said firstand second vertebral engaging portions each include a pair of holesextending between said upper and lower surfaces, said pair of holesbeing located on opposite sides of said longitudinal axis.
 5. The systemof claim 1, wherein said first vertebral engaging portion includes afirst transverse wall extending along said window between said first andsecond intermediate portions and said second vertebral engaging portionincludes a second transverse wall extending along said window betweensaid first and second intermediate portions.
 6. The system of claim 5,wherein said guide member extends from said second transverse walltoward said first vertebral engaging portion and said receptacle extendsthrough said first transverse wall into said second vertebral engagingportion.
 7. The system of claim 6, wherein said guide member includes arectangular body received in a rectangularly shaped opening of saidreceptacle.
 8. The system of claim 7, wherein said guide member includesa toothed surface along at least one side thereof and said receptacleincludes at least one retaining lip projecting into said opening of saidreceptacle and engageable to an adjacent tooth along said toothedsurface to limit movement of said first and second vertebral engagingportions away from one another.
 9. The system of claim 1, wherein one ofsaid first and second vertebral engaging portions defines a passagetherethrough along said longitudinal axis and said guide member includesa mounting portion positionable in said passage to engage said guidemember with said respective vertebral engaging portion with a bodyportion of said guide member extending into said window toward the otherof said first and second vertebral engaging portions.
 10. The system ofclaim 9, wherein said mounting portion of said guide member includes apair of arms extending from said body portion, said pair of arms beingmovable toward one another for positioning into said passage, at leastone said arms including an engaging flange adjacent an end thereof forengaging an enlarged portion of said passage when said engaging flangeis aligned therewith and said pair of arms are in said passage.
 11. Thesystem of claim 10, wherein said pair of arms each include a flangeprojecting outwardly therefrom adjacent an end of said respective armremote from said body portion of said guide member, said flangesengaging said enlarged portion of said passage to secure said guidemember in said passage.
 12. The system of claim 1, wherein when saidplate body is uncompressed along said longitudinal axis said guidemember is positioned outside said receptacle and when said plate body iscompressed along said longitudinal axis to move said vertebral engagingportions toward one another said guide member is received in saidreceptacle.
 13. The system of claim 12, wherein said receptacle includesa retaining lip and said guide member includes a toothed surfaceengageable with said retaining lip when said guide member is positionedin said receptacle to limit movement of said first and second vertebralengaging portions away from one another.
 14. The system of claim 1,wherein said receptacle includes a number of teeth extending thereacrossand said guide member includes a retaining member engageable with anadjacent one of said teeth when said guide member is received in saidreceptacle, said engagement between said retaining member and said teethlimiting movement of said vertebral engaging portions away from oneanother.
 15. The system of claim 14, wherein said retaining member is aspring.
 16. The system of claim 15, wherein said receptacle includes aslot opening therein for accessing said spring to disengage said springfrom said teeth.
 17. The system of claim 1, wherein said plate body iscomprised of a non-metal material and said guide member and saidreceptacle are comprised of metal material, said plate body being moldedaround said guide member and said receptacle.
 18. The system of claim 1,wherein said guide member and said receptacle are formed with said platebody to provide a unitary structure with said plate body.
 19. A spinalplating system, comprising: a plate body extending along a longitudinalaxis between a first end and an opposite second end, said plate bodyhaving a length along said longitudinal axis sized to extend between atleast a first vertebra and a second vertebrae of the spinal column,wherein said plate body includes: a first vertebral engaging portionwith at least one hole extending between an upper surface and a lowersurface of said plate body, said at least one hole for receiving ananchor to secure said first vertebral engaging portion to the firstvertebra; a second vertebral engaging portion with at least one holeextending between said upper and lower surfaces of said plate body, saidat least one hole for receiving an anchor to secure said secondvertebral engaging portion to the second vertebra; at least oneintermediate portion extending between said first and second vertebralengaging portions, said at least one intermediate portion includingopposite ends immovably fixed with respective ones of said first andsecond vertebral engaging portions to form said plate body with aone-piece unitary structure, wherein said at least one intermediateportion is structured to deform and permit said first and secondvertebral engaging portions to move toward one another along saidlongitudinal axis in response to compression loading of said plate bodyalong said longitudinal axis wherein said at least one intermediateportion includes first and second intermediate portions along oppositesides of said plate body, each of said first and second intermediateportions being integral with said first and second vertebral engagingportions to form said one-piece unitary structure, wherein each of saidfirst and second intermediate portions is structured to deform laterallyoutwardly away from said longitudinal axis and permit said first andsecond vertebral engaging portions to move toward one another along saidlongitudinal axis in response to compression loading of said plate bodyalong said longitudinal axis; and a guide assembly extending between andengaged to said first and second vertebral engaging portions, said guideassembly including a guide member movably received in a receptacle assaid first and second vertebral engaging portions move toward oneanother.
 20. The system of claim 19, wherein said first and secondintermediate portions are each convexly curved away from saidlongitudinal axis of said plate body to form a shape that is bowedlaterally outwardly away from said longitudinal axis in a direction fromsaid first vertebral engaging portion toward said second vertebralengaging portion.
 21. The system of claim 19, wherein said receptacleand said guide member engage one another to resist said first and secondvertebral engaging portions from moving away from one another.
 22. Thesystem of claim 19, wherein said first and second intermediate portionsand said first and second vertebral engaging portions defining a windowtherebetween that opens at said upper and lower surfaces of said platebody.